A Schubert condition in the Grassmannian $Gr(k,n)$ is encoded either by a partition $l$ or by a bracket $b$.
A partition is a weakly decreasing list of at most $k$ nonnegative integers less than or equal to $n-k$. It may be padded with zeroes to be of length $k$.
A bracket is a strictly increasing list of length $k$ of positive integers between $1$ and $n$.
This function writes a bracket as a partition. They are related as follows $b_{k+1-i}=n-i-l_i$, for $i=1,...,k$.
i1 : b = {1,3};
|
i2 : n = 4; |
i3 : bracket2partition(b,n)
o3 = {2, 1}
o3 : List
|
i4 : n = 6; |
i5 : bracket2partition(b,n)
o5 = {4, 3}
o5 : List
|
i6 : b = {2,4,6};
|
i7 : bracket2partition(b,n)
o7 = {2, 1, 0}
o7 : List
|
The object bracket2partition is a method function.